Figure 1.

Norepinephrine inhibits cytokine production in splenocytes via the β2-adrenoceptors. A) Adult male mice underwent sham surgery (control) or VNS. Epinephrine (E) and norepinephrine (NE) plasma levels were analyzed by ELISA at 15 min after stimulation. *P < 0.01 vs. control; Mann-Whitney U test (n=4/group). B) Primary cultures of splenocytes were treated with LPS (100 ng/ml) and E or NE. C) Primary cultures of splenocytes were treated with β-blockers, propranolol (PR) and nadolol (NA), or α-blocker, phentolamine (PH), 30 min prior to LPS and NE. D–F) Primary cultures of splenocytes were treated with β1-blocker, atenolol (AT; D), β2-blocker, butoxamine (BU; E), or β3-blocker, SR59230A (SR; F). In all the experiments, blockers were administered 30 min prior to LPS and NE, and TNF concentrations were analyzed in the conditioned medium at 3 h after treatment. Top panels represent cell survival as determined by MTT assay. *P < 0.01; 1-way ANOVA with Bonferroni's corrections (n=4).